Rodents

Rats and mice are found wherever there is food and shelter. The availability of such resources dictates population density. In ideal conditions, a pair of mice can produce more than 2000 offspring and a pair of rats 200 per year. Their gestation period is only 21 days and therefore population explosions can occur when effective control is not implemented.

In Britian the house mouse (Mus domesticus) is the predominant species. The house mouse weighs around 25-30gm and measures 60-90mm, its tail being 80-100mm long. it lives both indoors and outdoors, its diet consisting mainly of cereals. It can survive without drinking water, gaining sufficient moisture from its food. Eating only small amounts of only one thing at a time, its total food consumption is some 5gm per day.

Rattus rattus the black rat is no longer considered a major pest species in the UK. Found only in significant numbers at ports.

Rattus norvegicus, the brown, common or Norway rat is the largest and most dominant rat species in the UK. It weighs in at 500gm, and measures 200-250mm, the length of the tail being 150-200mm. It has small eyes, a rounded snout and is truly omnivorous, eating 50gm of food a day. Found living near water, in buildings and in sewers, it nests in burrows underground. Whilst not as agile as the black rat, the brown rat is nevertheless a good climber. It lives for 9-18 months and produces around 7 litters a year with 8-10 young in each. Rats also need to drink daily, with a typical intake of about 20ml.

A thorough understanding of the physical abilities of rodents is very useful when designing a control programme. For instance, rats are excellent swimmers. They can swim up to half a mile in open water, travel through sewer lines against substancial currents and tread water for up to three days. Climbing is also easy for them. If they can't climb, they just jump. From a standing position rats can jump vertically up to three feet - and getting down is easy. If necessary, rodents can drop from heights of 50 feet without injury. If rodents can't get around an object, they go through it. Rodents are capable of gnawing through a variety of materials including lead sheathing, cinderblock, aluminium siding, glass and improperly cured concrete. Rodents can also squeeze through very small openings.

All of these physical abilities have allowed rats and mice to survive hundreds of years in man's environment. The following are some of the other sensory abilities that make rodents so remarkably adaptable.

Rodents use hearing to locate objects to within a few inches. Rats and mice have a frequency range of 50 kilohertz or more, which is much higher than humans who have a range of about 20 kilohertz. Rodents make high frequency noises in various situations such as in mating but the function of these sounds is poorly understood.

Rats and mice have poor vision beyond three or four feet but they are very sensitive to motion up to 30-50 feet away. For the most part, rodents are colour blind but very light-coloured or reflective objects may stand out in their environment and cause initial avoidance amongst sensitive rodents.

Rodents have a highly developed sense of taste, which allows them to detect some chemicals at parts-per-million concentrations. This taste sensitivity may lead to bait rejection if the baits are contaminated withinsecticide odours or other chemicals. Use of fresh, food quality grain ingredients is the best guarantee of good bait attractability and acceptance.

Odour is one of the rodents most important senses. Rodents mark objects and pathways to and from food sources, members of the opposite sex, who are ready to mate, differentiate between members of their own colonies and strangers and to tell if a stranger is a strong or weak individual.

Rodents have a highly developed sense of touch due to very sensitive body hairs and whiskers (vibrissae), which they use to explore their environment.

Control tecniques should be designed to eliminate the infestation completely, since any remaining rodents will produce a rapid reinfestation. Control tecniques can be chemical and non-chemical. Non-chemical tecniques may be used on their own, such as the utilisation of live traps, glue boards and traditional back breakers but more often these methods are used to complement chemical control. Some additional non-chemical tecniques such as ultrasound have not been proven to be as effective as long-term control measures.

The use of rodenticidal contact dusts, gels, baits and traps will, when used professionally control an ongoing rodent infestation. AG pest Management staff have many years experience in eradicating rodent infestations successfully.

Contact AG Pest management staff for a cost effective solution to your pest problems.